A conventional system for landscape watering comprises sprinkler heads that are arranged in an array over the area to be watered wherein each head is connected to a network of underground pipes that supply the water. Present practice is to use conventional plumbing hardware, such as: rigid or semi-rigid angles, Tees, ells, rigid nipples, unions and the like in order to connect the sprinkler to the water pipes. However, this construction is subject to numerous problems and inconveniences. For example, laying out and accurately cutting pipe nipples and arranging Tees, angles, etc., is very tedious and expensive in terms of labor costs and hardware.
An example of the disadvantages of present practice is the high degree of skill and the high cost of labor that is required to properly dig trenches, not only for the lateral supply pipe downstream of the valve assembly, but also for the branches of pipe leading from the lateral supply pipe out to each sprinkler head. In general, it is necessary to dig straight or extra wide trenches because the rigid pipe is straight. However, this becomes virtually impossible because of rocks, tree roots, foundations, buried cables or other objects. Where such obstacles are encountered, the trench must be dug, typically by hand, around and at a safe and appropriate distance from the object. Then pipe must be cut to fit, and elbows, angles, Tees, nipples, unions and the like must be glued or threaded in place. If the pipe is displaced or twisted, the entire watering pattern is in disarray with patches of over- and under-watering.
Great care must be taken when trenching in order to avoid striking underground obstacles such as main water service lines, electrical service lines, gas service lines, etc, as trenching requirements reach 16", 24", or more. Deep trenches require a greater amount of labor and equipment. Open, deep trenches are a safety hazard on any jobsite. Further, trenches must be cleaned out repeatedly by hand, due to foot traffic in the work area, inadvertently knocking dirt, rocks, and debris into the trenches. Also, to prevent costly damage by or to trenching tools and equipment, trenches must be dug at a reasonably safe and appropriate distance away from such obstacles as sidewalks, curbs, driveways, planting borders, and the like. Since most sprinkler heads are located within a few inches from sidewalks, curbs, driveways, etc., the remaining trenching to these locations is almost always done by hand. Trenching is not only the most hazardous and time consuming part of installing an underground sprinkler system, but also requires a great deal of care and skilled labor.
A particularly serious problem is that during assembly of conventional sprinkler systems, the feed-pipe (lateral line) is constantly being moved around in the trench because various Tees, nipples and sprinkler heads are being attached to it along its length. As each section of pipe is cut to length to fit various unions, Tees, etc., the pipe is lifted out of the trench and the next piece is attached, typically by eye, and is easily subject to misalignment. The feed-pipe is cut, and elbows, angles, tees, nipples, unions, and the like must be glued or threaded into place, and then the sprinkler head is attached. The time to measure, calculate, cut, assemble, and fasten becomes extensive. This process repeats itself when the next sprinkler head is to be attached; however, while handling the feed-pipe for the next sprinkler head assembly, the sprinkler head (or heads) previously assembled and set into place, will unavoidably be disturbed.
The pipe has some lateral flex, typically snaking along even the straightest of trenches resulting in misalignment of the heads. But the sprinkler head placement needs to be in a predetermined, relatively regular array to give proper coverage without overlap or gaps in coverage. Thus, when the fixed-length lateral nipples and elbows are attached to the feed pipe, followed by vertical nipples, transitions and sprinkler heads, the final sprinkler head array is usually misaligned to some degree, often significantly so.
Another problem which adds to the misalignment of the sprinkler heads occurs when the trenches are backfilled. After all underground piping is completed, the trenches are backfilled with soil, and packed firmly. Care must be taken not to disturb the piping which can easily shift its position in the trench when soil is backfilled. Since the feed-pipe, Tees, Ells, nipples and sprinkler heads have all been glued and fitted together, and since the sprinkler heads have been positioned in place, there can be no shifting of pipe allowed while backfilling. Even the most carefully assembled sprinkler system will have severe alignment and or poor coverage if the backfilling is carelessly done, and the piping and sprinkler heads are cause to shift out of position. This can also cause tortional cracking of rigid pipes, or even cause shear-off of entire sections or individual sprinkler heads.
Equally significantly, the feed pipe Tees are typically, indeed almost always, angularly improperly aligned. That is, viewing the feed pipe in cross-section at the bottom of the trench and taking the longitudinal axis of the pipe as the center of the pipe, the side arm of the Tee to feed a given sprinkler head must be relatively precisely angularly positioned for a given job, be it at 0.degree. (upward vertical feed), 30.degree., 45.degree., 90.degree. (right side feed, viewed clockwise), 270.degree. (left side feed), or some angular amount .+-. the 90.degree. or 270.degree.60 position. If the Tee is not angularly properly positioned, then the nipple, elbow and sprinkler head will be cocked at an angle, as well as buried or elevated aboveground. While current nipples and transitions come in joined segmented units, the units are exactly that; they have preset unit length that does not permit accurate intermediate placement.
Thus, the pipe not only snakes sideways in the trench, but also up and down as rocks or clumps of earth are used to prop it up to compensate for poor tee/nipple/elbow/head assembly. More seriously, the pipe is rotationally twisted (placed under torsional stress) for proper vertical and angular placement of the sprinkler heads. The next adjacent heads along a single feed pipe are often torsionally stressed in opposite, rotationally angular directions. While the pipe can stand some lateral bending, it is less able to handle torsional (rotational or twisting) stresses, thus leading to failure in service. This failure is aggravated by settling of the pipe as the trench fill compacts over time, or the pipe is driven-over by vehicles (cars, lawn tractors, etc). While use of thin wall (Schedule 20), instead of heavy duty (Schedule 40) pipe provides some flexibility, it is even less able to handle such torsional or loading stresses, and is easily punctured by rocks, spades, etc.
The entire problem is aggravated where the layout requires the feed pipe (manifold) to turn corners. This is the case in almost 100% of the cases. An angularly improperly oriented 90.degree.60 elbow thus affects at least one entire branch of the line.
Further, sprinkler arrays must be laid out in 3-dimensions. That is, the land is rarely flat, yet sprinkler heads must all be positioned properly with respect to ground level which varies throughout the field being sprinklered. The rigid/semi-rigid, pipe/elbow/nipple/head systems offered today simply do not permit proper placement without very careful prior layout and skilled assembly of parts. Even so, the unit-length problem does not permit proper final adjustment.
All these problems are made more severe by the use of unskilled labor. It takes brains and experience to lay out and install a sprinkler system correctly. It looks simple, but it is hard and precision work. But landscape services hire laborers at minimum wage for digging the trenches. Being unskilled, not appreciating the problems, and often being relegated to such work because none too bright, the workers often do not do good or even adequate jobs in trenching, cutting pipe to length, and figuring out proper angular and lateral placement. They thus misalign, both laterally and angularly, the various lateral and main feed-pipes, Tees, nipples, Ells, heads, etc. The resulting job is poor, with overwatering and dry spots all in the same lawn, garden, etc. The workers leave an unhappy client, typically a homeowner, who does not want to pay. The sprinkler system installer looses jobs, the workmen drift on the other lines of work, and more inexperienced contractors spring up to leave another generation of shoddy jobs behind. Systems fail, leaks develop, and water, a particularly precious commodity in the West, is wasted.
Yet another problem is encountered when long "pop-up" sprinkler heads are to be installed. They are used to clear shrubs or tall plantings, rocks, walls etc. The body of many "pop-up" sprinklers require a hole that is eighteen inches or more deep. Thus, where these "pop-up" sprinklers are required, rather than setting the supply pipe at the usual 6-12" depth, the landscape contractor must install the entire lateral feed-pipe(s) array at a depth of eighteen or more inches. That is no less than 3 times the digging, and the angular misalignment problems are made even more severe, as fractional angular errors are multiplied over the greater length of the heads, nipples, etc.
Other problems include: frequent breakage of the sprinkler head when the head is inadvertently kicked; growing grass interferes with the flow of water from the head; the height of the head above the ground is not accurately set and maintained. Many of these problems are discussed in Sunset Magazine, June 1986, published by the Lane Publishing Company.
The prior art does not either recognize or solve these problems. Indeed the prior art found has focused on the prevention of damage due to inadvertently striking the sprinkler head. The prior art has generally ignored the problem of excessive labor and cost associated with rigid structures of preset unit length.
For example, U.S. Pat. No. 3,759,445, discloses a short, only semi-flexible connection positioned below ground level to the sprinkler head from a water pipe so that if the sprinkler head is accidentally struck, the connection will yield without breaking. Because of its intended purpose, this semi-flexible connector is only a few inches long, and will collapse or kink when the bend is severe. Furthermore, the positioning of the sprinkler head is unstable relative to the surface of the ground.
The semi-flexible connection disclosed in U.S. Pat. No. 2,582,249, provides resistance to kinking but is only slightly flexible, so that placement of the sprinkler relative to the water pipe is severely limited.
The corrugated constructions of U.S. Pat. Nos. 2,582,250 and 4,314,718 and 4,314,717 are only semi-flexible and do not provide strength against puncture by spades or high water pressure. It also does not prevent what is required in many situations: collapsing or kinking due to bending or an inadvertent blow from a passing machine or pedestrian.
U.S. Pat. No. 3,904,120, discloses a sprinkler head recessed into a heavy disk that is set into the ground and provides an anchor for the sprinkler head. However this device does not address the problem of requiring accurate dimensioning of nipples and fittings regarding the placement of the sprinkler relative to the water pipe. Furthermore, the sprinkler head is incorporated integrally into the disk so that choice of sprinkler head is restricted.
U.S. Pat. No. 4,669,508, discloses a heavy, permanently curved hose for automobile cooling systems and therefore does not provide the flexibility required for the purposes of this invention.
U.S. Pat. No. 4,256,262 discloses a light duty connector between a water supply pipe lying above ground and a sprinkler head that is supported several feet above ground on a special spiked stand.
Other patents such as U.S. Pat. Nos. 4,256,262; 2,752,195; 4,382,556; and 4,095,744 are designed for above-ground construction. A number of couplings, disclosed in U.S. Pat. Nos. 4,165,109; 3,843,169; 3,614,137; 3,224,794; are designed for purposes other than those of the present invention. There are also references U.S. Pat. Nos. 4,179,171; 4,033,614; 3,346,274; 3,363,319: 2,807,478: that pertain to rigid coupling means that do not address the problems that are resolved by this invention.
It is apparent, therefore, that none of these patents address the problem of reducing the cost and labor associated with the current procedures used to install sprinkler systems.